Mark C. Posted July 31, 2019 Report Share Posted July 31, 2019 Baruim has a feel that only baruim has-comapare that to a known bag of baruim-it feels very unique over other materials. It feels clamy and clumpy I have alarge bag of it and its easy to feel the difference against other white powders Link to comment Share on other sites More sharing options...
MFP Posted July 31, 2019 Author Report Share Posted July 31, 2019 Back in the day, barium was all we had....we did not have Strontium.....until I started looking at recipes on here and glazy,, I had never hear of it before. Also nepheliine syenite. So if you wanted a crystal clear celadon.....you used barium. Celadon was one of the glazes I used the most. I actually don't have much of #3.....maybe 10 pounds. It's #5 that I have 50 pounds of. #1 about 20 pounds. That's another reason I think #3 might be barium......it was almost used up. I suppose it could be Kingman. But I don't think that would fuse at 04. I have made up batches of that glaze PeterH posted for me with all three substances. I found a recipe on glazy: 50 gerstley, 35 silica, 15 EPK.....then 20 Bentonite, 10 chrome oxide and 10 cobalt carbonate. I am assuming the last three on typos and should be 2, 1 and 1? Right? Link to comment Share on other sites More sharing options...
MFP Posted July 31, 2019 Author Report Share Posted July 31, 2019 Yes...that is exactly what it looks like which is why I think that is what it is. It was however slightly cream colored....could be the batch or age. My other barium is white. If you noticed in the pics, both 1 and 3 had that same lumpy appearance....which is what made me think they were both carbonates. I looked at that digitalfire chart and barium does not lose mass whereas calcium carb does. The fine grained sandy feel to #5 makes me think either dolomite or bone ash. I have 50 pounds of the stuff. So I made up three glaze samples of that glaze PeterH posted. Link to comment Share on other sites More sharing options...
liambesaw Posted July 31, 2019 Report Share Posted July 31, 2019 27 minutes ago, MFP said: Back in the day, barium was all we had....we did not have Strontium.....until I started looking at recipes on here and glazy,, I had never hear of it before. Also nepheliine syenite. So if you wanted a crystal clear celadon.....you used barium. Celadon was one of the glazes I used the most. I actually don't have much of #3.....maybe 10 pounds. It's #5 that I have 50 pounds of. #1 about 20 pounds. That's another reason I think #3 might be barium......it was almost used up. I suppose it could be Kingman. But I don't think that would fuse at 04. I have made up batches of that glaze PeterH posted for me with all three substances. I found a recipe on glazy: 50 gerstley, 35 silica, 15 EPK.....then 20 Bentonite, 10 chrome oxide and 10 cobalt carbonate. I am assuming the last three on typos and should be 2, 1 and 1? Right? Uhh yeah, if you added 20 parts bentonite to anything you'd have a real mess. Same with 10 cobalt or chrome. I would be worried about 50 gerstley as well, that seems excessive. Is this some kind of fake ash or super runny glaze? There's so little alumina. It sounds more like a cone 06 glaze as opposed to cone 6! Either way, with 50 gerstley and 15 epk there's no way in heck you need any bentonite. It'll be as thick and goopy as snot without it, may even need to deflocculate it. Link to comment Share on other sites More sharing options...
MFP Posted July 31, 2019 Author Report Share Posted July 31, 2019 It was on glazy-- Mayan Deep Blue....supposedly a cone 9/10 glaze.....Remember....my glossy white was 50 colemanite and 50 PV clay and 15 zircopax. We used it from raku all the way to 10. I probably have the only colemanite in the US! Link to comment Share on other sites More sharing options...
liambesaw Posted July 31, 2019 Report Share Posted July 31, 2019 38 minutes ago, MFP said: It was on glazy-- Mayan Deep Blue....supposedly a cone 9/10 glaze.....Remember....my glossy white was 50 colemanite and 50 PV clay and 15 zircopax. We used it from raku all the way to 10. I probably have the only colemanite in the US! That one makes more sense since zircopax is highly refractory. Too bad about the PV mine eh? Link to comment Share on other sites More sharing options...
Mark C. Posted July 31, 2019 Report Share Posted July 31, 2019 I can do a kingman test at cone 08 or cone 10 when i get back to clay later in August if that helps. I still use kingman although I'm down to under 500#s now. Link to comment Share on other sites More sharing options...
MFP Posted July 31, 2019 Author Report Share Posted July 31, 2019 That would be great if you could Mark because I am not doing my gas fire until this winter. I want to be able to open the door to vent it. It gets so cold here....it will just be sucked right out the door.....no need for a vent. I hope you have a wonderful show! Link to comment Share on other sites More sharing options...
MFP Posted July 31, 2019 Author Report Share Posted July 31, 2019 I got PV clay from the ceramics store. I have a whole gallon jug of it. I mixed up my glaze to verify Mark's finding that substance #2 was zircopax. It will mature at 6. Link to comment Share on other sites More sharing options...
Min Posted July 31, 2019 Report Share Posted July 31, 2019 19 hours ago, MFP said: I am thinking that #3 is barium carbonate. Unlike calcium carbonate, it loses no weight/mass on ignition. Nope, carbonates by their nature have a loss on ignition. I believe there is a typo in the link from Digitalfire for the LOI for barium carbonate, it won't be zero as in the chart from that page. Oxide analysis formula for barium carbonate is BaO 77.66 CO2 22.34 therefore the LOI will be 22.34 Link to comment Share on other sites More sharing options...
PeterH Posted July 31, 2019 Report Share Posted July 31, 2019 2 hours ago, Min said: Nope, carbonates by their nature have a loss on ignition. I believe there is a typo in the link from Digitalfire for the LOI for barium carbonate, it won't be zero as in the chart from that page. Oxide analysis formula for barium carbonate is BaO 77.66 CO2 22.34 therefore the LOI will be 22.34 Min, I think that both you and Digitalfire are right "up to a point". After some googling ... From http://chemisphere.co.uk/index.php?route=product/product&product_id=57 Loss on Ignition (800C x 1hr) 0.4% Max From https://books.google.co.uk/books?id=Qq3zCAAAQBAJ&pg=PA129&lpg=PA129&dq=barium+carbonate+loss-on-ignition&source=bl&ots=xK72KoHSho&sig=ACfU3U3_HZ2qQlEQnFWpoocnIHDJWmwSFg&hl=en&sa=X&ved=2ahUKEwi8uba9n9_jAhVIQ8AKHU-JCQcQ6AEwC3oECAkQAQ#v=onepage&q=barium carbonate loss-on-ignition&f=false Loss on ignition 22.3% ... decomposition of BaCO3 at 1450C (2640F) So the potential LOI is, as you say, 22.3%, however how much happens depends on the temperature use (and no heat-work). See fig2 in http://www.scielo.br/pdf/ce/v54n331/a0154331.pdf Finallyhttps://www.chemguide.co.uk/inorganic/group2/thermstab.html discusses why the dissociation temperature of the alkali metals increases Mg<Ca<Sr<Ba in terms of the larger ions having less ionic potential and hence less polarising effect on the carbonate ion. Link to comment Share on other sites More sharing options...
Min Posted July 31, 2019 Report Share Posted July 31, 2019 That's interesting Peter. From this it seems like barium carb melts at around 1300F, so well before the decomposition happens, interesting! Extrapolating from all this the LOI figure given for barium carb (screenshot of LOI from Insight below) is only going to be valid if the barium is included in a glaze melt and effected by eutectics or is heated to 1460C. Link to comment Share on other sites More sharing options...
MFP Posted July 31, 2019 Author Report Share Posted July 31, 2019 Thanks digitalfire chart said no loss on ignition. Link to comment Share on other sites More sharing options...
MFP Posted July 31, 2019 Author Report Share Posted July 31, 2019 I have made up samples of that glaze Peter posted with all three substances....so...hopefully that will give us some clues. Don't know if you saw the pictures of the fused material. Here it is again. The fused one is the center one. I thought it was interesting that #5 turned pink.....it has iron in it somewhere. Both 1 and 5 remained powders that could be removed from the pots. Link to comment Share on other sites More sharing options...
PeterH Posted July 31, 2019 Report Share Posted July 31, 2019 3 hours ago, Min said: That's interesting Peter. From this it seems like barium carb melts at around 1300F, so well before the decomposition happens, interesting! Extrapolating from all this the LOI figure given for barium carb (screenshot of LOI from Insight below) is only going to be valid if the barium is included in a glaze melt and effected by eutectics or is heated to 1460C. [I may be reading your ref too quickly, but is seems to say metallic barium melts at ~ 1300F. However as wiki gives the MP of BaCO3 as 811C (1,492F) your point remains a good one.] Many years ago I was astounded to read that quite a lot of the barium sulphate in a Jasper body survived the firing. I'd assumed that it would simply decompose. Trying to find a reference I looked in "Ceramic Masterpieces" and found this:During firing at a temperature of about 1250C, a portion of the barium sulfate reacts with the clay components to form a barium-aluminium-silicate matrix containing residual barium sulphate particles. The matrix is a mixture of a glass with fine particles of barium-aluminium-silicate (celsian) and barium silicate (sanbornite) ... From which I assume that the barium sulphate in the body either remains unchanged† or enters into the molten glassy matrix liberating SO3 (later the barium micro-crystalises out on cooling). It would make sense if the barium carbonate in a glaze did much the same. So in high-alkali raku turquoises the BaCO3 would be completely decomposed, while in a full-blown barium matt perhaps some unchanged BaCO3 remains. Just a guess. Regards, Peter † Wiki gives the MP of BaSO4 as 1,580C (2,880F) and https://chemiday.com/en/reaction/3-1-0-3287 gives the decomposition temperature as "over 1580C". Link to comment Share on other sites More sharing options...
MFP Posted August 1, 2019 Author Report Share Posted August 1, 2019 Min.....any chance that the fused material is a clay at that temp? Link to comment Share on other sites More sharing options...
Min Posted August 1, 2019 Report Share Posted August 1, 2019 5 minutes ago, MFP said: Min.....any chance that the fused material is a clay at that temp? Did you have lowfire clay in your studio back then? Link to comment Share on other sites More sharing options...
MFP Posted August 1, 2019 Author Report Share Posted August 1, 2019 No but I used a LOT of PV clay in that one glaze recipe and thought it was odd that I did not see a can labeled with it. I do think I had one recipe that called for china clay. Link to comment Share on other sites More sharing options...
Min Posted August 1, 2019 Report Share Posted August 1, 2019 For the one you think might be plastic vitrox a simple test would be to mix it up 50:50 with your colemanite and see if you get a clear gloss at cone 6. PV has a very low LOI and gives a pinkish colour at ^6. I don't know if you've come across it already but good article on PV clay here that might give you some more clues if that's what it is. Link to comment Share on other sites More sharing options...
MFP Posted August 1, 2019 Author Report Share Posted August 1, 2019 AHA! One of them did turn pink in the LOI test! What through me off is that the PV clay I recently got was a slightly tan color. Yes....I will try that with all three samples. Thank you Min for your input and resources! Link to comment Share on other sites More sharing options...
MFP Posted August 1, 2019 Author Report Share Posted August 1, 2019 37 minutes ago, Min said: For the one you think might be plastic vitrox a simple test would be to mix it up 50:50 with your colemanite and see if you get a clear gloss at cone 6. PV has a very low LOI and gives a pinkish colour at ^6. I don't know if you've come across it already but good article on PV clay here that might give you some more clues if that's what it is. It actually mentions that glaze in the information page with gerstley as a substitute for colemanite. "The flux content, low iron and plasticity of PV Clay made it a practical glaze material also. A simple 50:50 mix of PV Clay and Gerstley Borate was used widely as a transparent glaze at cone 5-7. A mix of 80:20 PV and calcium carbonate produces a cone 10 transparent glaze." Link to comment Share on other sites More sharing options...
MFP Posted August 8, 2019 Author Report Share Posted August 8, 2019 It occurred to me today that one of these might be Kona F4 feldspar. I saw it in a recipe and remembered that I used to use it. I followed Min's suggestion and made up a sample of my white glaze without the zircopax to see how these three things act with 50 Colemanite. I am getting close to the first cone 6 fire. Link to comment Share on other sites More sharing options...
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